This invention relates to polysulfone copolymer compositions having polymer segments covalently bonded and to a process for producing the polysulfone copolymer compositions. More particularly, this invention relates to polysulfone copolymer compositions wherein the copolymer is present throughout the solid bulk material of the composition. Sulfone polymers, such as polysulfone, polyethersulfone and polyphenylsulfone are tough amorphous polymers which are useful in a wide variety of applications including molded products, printed circuit wiring board substrates and in environments where resistance to caustic or acid is desirable. It would be desirable to modify the bulk properties of polysulfones, including chemical properties and physical properties to permit additional applications for the modified sulfone polymer.
At the present time, polysulfone grafted membranes have been prepared by modifying the surface of a solid polysulfone membrane with a polymerizable monomer to form a graft only on the membrane pore surface. The remaining portion of the membrane comprises unmodified polysulfone polymer. U.S. Pat. No. 5,468,390; Journal of Membrane Science, 105(1995), p. 237-247 and Journal of Membrane Science, 105 (1995, p. 249-259) disclose modified aryl polysulfone membranes having a hydrophilic vinyl monomer chemically grafted to their surfaces. An unmodified membrane is contacted with a solution of the monomer and is exposed to ultraviolet light to effect photochemical grafting in the absence of a sensitizer or a free radical initiator. The monomers utilized function to render only the polysulfone membrane surface hydrophilic. The remaining portion of the membrane bulk matrix comprise unmodified polysulfone. These modified membranes are not rewettable after they have been dried and, if dried, lose significant permeability. Therefore it is necessary to maintain the membrane surfaces wet prior to use. Japanese Pat. No. JP-A-2-59029, published Feb. 28, 1990, discloses a process for modifying a polysulfone porous membrane on its surface only with a polymerizable monomer by immersing the membrane in the monomer solution and irradiating the solution with ultraviolet light. The process is conducted under conditions such that any solvent used in the process does not dissolve the polysulfone membrane. As a result of the process, only the surface of the porous membrane is modified to render it hydrophilic when hydrophilic polymerizable monomers are utilized in the process. As is the case with the modified polymers disclosed in U.S. Pat. No. 5,468,390, the modified membrane surfaces cannot be dried without a serious loss of permeability.
Accordingly, it would be desirable to provide modified polysulfone compositions which are modified throughout their bulk matrix. In addition, it would be desirable to provide a process for forming such compositions which can be used with a wide variety of polymerizable monomers to produce polysulfone copolymer compositions having polymer segments covalently bonded.